WASHINGTON — The government, still struggling to manage a severe financial crisis, unveiled two new programs Tuesday that will provide $800 billion to try to help unfreeze the market for consumer debt from home mortgages to credit cards.

The announcements by the Federal Reserve and the Treasury Department represented the latest modifications to the largest government bailout in history, a program designed to keep the troubled financial system from dragging the country into a deep and prolonged recession.

Treasury Secretary Henry Paulson has been criticized for continually revising the focus of the government's response to the crisis.

Paulson on Tuesday defended all the changes, saying that there was no one response adequate by itself to deal with what he termed a once- or twice-in-a-century financial crisis. He said that was why the government was having to keep modifying its response.

"It is naive for any of us to think that when you are dealing with a situaiton of this magnitude that a bill could be passed or a single action taken to make all the issues go away," Paulson told reporters at a briefing on the new programs.

To try to increase the availability of home loans to borrowers, the Federal Reserve said it will buy up to $100 billion in direct obligations from mortgage giants Fannie Mae and Freddie Mac as well as the Federal Home Loan Banks. The Fed also will buy $500 billion in mortgage-backed securities, pools of mortgages that are bundled together and sold to investors.

The program on consumer debt will lend up to $200 billion to the holders of securities backed by various types of consumer loans. It will be supported by $20 billion of credit protection from the $700 billion bailout package that was enacted last month.

The government, while looking to reduce fear in the credit markets, is eager to see lenders like credit card companies resume more normal levels of lending to help stimulate the economy. Since September, when credit markets first froze, financial institutions have been hesitant to hand over money for fear they won't be repaid.

On Wall Street, the new government efforts provided an early lift to stocks, but the Dow Jones industrials were down about 10 points in midday trading.

Meanwhile, data released Tuesday provided further proof the country is almost certainly in the throes of a painful recession.

The Commerce Department's updated reading on the economy's performance showed gross domestic product shrank at a 0.5 percent annual rate in the July-September quarter, weaker than the 0.3 percent rate of decline first estimated a month ago, and the worst showing since the third quarter of 2001.